Electronic tube



2 Sheets-Sheet l y M. ORLOVE ELECTRONIC TUBE June 15, 1948.

Filed Nov. 7, 1942 June 15,1948. MI ORLOVE 2,443,324

ELECTRONIC TUBE Filed NOV. 7, 1942 2 Sheets-Sheet 2 INVENTOR. MA X .ORL O l/E Patented June 15, 1948 UNITED STATES PATENT OFFICEy 2,443,324 ELECTRONIG TUBE Max Orlove, New York, N. Y., assignor of onehalf to Charles Schiffman, New York, N. Y.

Application November 7, 1942, Serial No. 464,840l

13 Claims. (Cl. 176-122) This invention relates to electronic tubes. More particularly, Ithe invention pertains to electronic tubes of the type in which the conventional fragile incandescent filament is supplanted by an electronemissive substance energized by means other than an extremely high temperature.

One of the objects of the invention is to provide an improved tube of the .character described which is light in weight and rugged in design, consumes relatively little power for releasing electrons, is highly sensitive, and is adapted to be eiiciently employed in the usual circuits in which present-day electronic tubes can be used.

Another object of the invention is to provide a tube of the character described in which electrons are released from the electron-emissive substance under the influence of only a moderate or mild temperature of the order lof that generated in or by a glow discharge. v

Another object of the invention is to provide a tube of the character described in which a plurality of separate groups of tube elements are contained in a single envelope and in which but a single means is employed to economically, simply and eiiicien-tly energize independent electronemissive elements associated with the several groups of tube elements.

A further object of the invention is to provide a tube of lthe character described which is particularly adaptable for use in roughly handled portable sets and in which the energy required to release electrons can be supplied by asource of light weight and small capacity.

Another object of the invention is -to provide a tube of the chara-cter described in which the electron-emissive substance is not electrically connected in the circuit in which the tube is employed., whereby the tube is rendered extremely sensitive, the tubes space charge and electron emission from coated surfaces is unaiected by current flowing through the heated filament, and the uneven emission of electrons due .to variation of potential applied to the heated filament is eliminated.

A still further object of the invention is to provide a tube of the character described in which the use of costly and critical metals, such as tungsten and nickel, is avoided.

Another object of my invention is to provide a tube of the character described which can operate even when the electrodes are enclosed in an unevacua-ted container.

Still another object of the invention is to provide a tube of the lcharacter described which is rendered highly sensitive by novel shielding.

Other objects of the invention will in part be obvious and in part hereinafter pointed out.

The invention accordingly consists in the features of construction, combinations of elements, and arrangement of parts which will be exemplifled in the constructions hereinafter described, and of which the scope of application will be indicated in the appended claims.

Certain features of the invention shown and described but not claim-ed herein are described and claimed in my copending application, Serial No. 464,841, for Electron tube coating, filed on the 7th day of November 1942, which issued September 30, 1947, as United States Patent Number 2,428,289.

In the accompanying drawings, in which is shown one of the various possible embodiments of this invention,

Fig. 1 is a side view in partial section of an electronic tube embodying my invention;

Fig. 2 is a sectional View taken substantially along the line 2-2 of one of the iinger tubes shown in Fig. 1;

Figs. 3 and 4 are enlarged sectional views taken substantially along the lines 3 3 and 4--4 respectively of Fig. 1;

Fig. 5 is an end view of one of the finger tubes;

Fig. 6 is an end View of a coupling socket adapted to be used therewith;

Fig. 7 is a view, similar to Fig. 1, of an electric tube embodying a modified form of my invention;

Fig. 8 is an enlarged sectional view taken substantially along the line 8-8 of Fig. 7;

Fig. 9 is a side View of an electronic tube embodying another modified form of my invention; and

Fig. 10 is a sectional view taken substantially along the line Ill-l0 of Fig. 9.

Referring now to the drawing-s, and more particularly to Figs. 1 through 6, wherein there is disclosed one .of the preferred forms of my invention, 20 denotes a compound -electronic tube embodying my invention. Said tube comprises a trunk tube 22 preferably fabricated from a dielectric substance, such as glass or a plastic. The trunk tube is elongated and has disposed at its two reduced ends cup-shaped electrodes 2li, 26 which are supported and adapted to be connected in circuit by lead-in wires L. The interior of the trunk tube 22 is filled with'an inert ionizable gaseous medium at a low pressure so that when a proper potential is applied to the electrodes 24, 26 a glow discharge will be maintained therebetween. 'Ihe potential supplied to the electrodes andthe type and pressure of gas contained with opening between the iinger tube envelope 34 and trunk tube 22.

The finger tube 3l) comprises a tubular glass envelope 64 having an integral, domed, imperforate bottom wall 66 which is fused to the wall of the trunk tube 22 and which projects well into the interior of said trunk tube so that it will lie in the path of and be bombarded by the electron stream between the trunk electrodes 24, 26. The opposite end of the glass tube 64 is retroverted to provide a press 68 which supports lead-in wires 'l0 for a cathode l2, grid 74, and plate '16. These three electrodes 'I2-16 comprise open-ended tubular elements concentrically arranged and preferably disposed coaxially of the tubular envelope 64. The cathode l2, which is outermost of the three electrodes, comprises a plurality of parallel spaced wires 18 arranged to form a cylinder and supported on spaced rings 19. The grid 14 is a metal screen and the anode an imperforate metal sheet.

The lead-in wires 'l0 are connected in the usual manner to prongs (not shown) in the base 80 of the finger tube 30. Said prongs are connected by a coupling, like that shown for the nger tube 28, to a socket in the circuit in which the tube 30 is to be employed.

The interior surface of the finger tube 36 is provided with an electron emissive coating like that described with reference to the iinger tube 28.

In the operation of the tube electrons emitted from the coating enter the space between the anode 16 and cathode 'l2 and conduct current therebetween, such current being controlled by the grid 14 in the well-known manner.

It will be appreciated that, due to the thermal capacity of the envelope 64, the coating is maintained at a uniform temperature and electronemission therefrom occurs at a uniform rate. This does away with the use of filter circuits heretofore employed to eliminate an A. C. hum caused by intermittent heating of a filament. Dispensing with a heater lament also eliminates interference arising from undesirable electronemission of the lament and passage of current therethrough.

The finger tube 32 comprises a glass tubular envelope 82 closed at one end by an imperforate domed bottom 84. Said tube is adapted to be snugly received in an annular flange 86 extending from the wall of the trunk tube 22. To provide better heat conductivity for the finger tube 32 and to thus increase the temperature to which its coating (similar to that of the other finger tubes) is raised, and increase electron-emission, I also employ a hemispherical metallic shell 99 projecting into the interior of the trunk tube and having a short integral tubular extension 92 which is fused to the interio-r of the annular flange 86 and seals the opening in said trunk tube. The shell 90 is of such configuration as to snugly receive the bottom of the nger tube 32.

Said finger tube is closed at its free end and is there provided with a retroverted press 94 in which the lead-in wires 96 are carried. The interior of the tube envelope, including the domed bottom 84, is provided with three metallic-coated segments 98 which may be of equal size and, together, cover substantially the entire inner surface of the finger tube with the exception of a narow space between the coatings. Each metallic segment is connected by a lead-in wire 96 to' a prong (not shown) in the base |60 of the finger tube 32. Each .metallic segment 98 has superimposed thereon a base layer |02 and an overlying electron-emlssive layer |84 such as were described with reference to the finger tube 28.

Intermediate adjacent edges of the metallic segments are electrically conductive barrier plates |86 which extend radially toward the center of the linger tube and are connected by lead-in wires S5 to prongs in the base of the tube. Said barrier plates physically separate the tube into a plurality of sectors. These barriers are adapted to be negatively charged during operation of the tube to electrically segregate said sectors and prevent groups of electrodes disposed in different sectors from interfering with each others operation.

Associated with each segmental electronemissive coating is a segmental screen wire grid i 68 which lies between the coating and the center of the tube and extends angularly between but does not touch the two barrier plates |96 which bound each sector. Each coating and grid also has associated therewith a segmental electrically conductive metallic anode lli) which lies closer to the center of the tube than the grid and, like the grid, does not touch the barrier plates. The segmental coating, grid, and anode comprise an electrode group. The three electrode groups in the nger tube 32 are concentrically arranged about the longitudinal axis of said tube. Obviously if other electrodes are employed in any electrode group they may be placed in proper rder within the boundaries deiined by the barrier plates 466 and metallic coating 98.

The same type of coupling means as was described with reerence to the finger tube 28 may be employed to detachably attach the prongs in the base 109 to various conventional sockets for electronic tubes.

It will be noted that in a nger tube of this construction a plurality of electrode groups are enclosed within a single tube so that said tube can replace several present-day electronic tubes. The number of electrode groups that can 'be contained -Within a single tube is only limited by the size of the tube and the nature of the circuit in which the electrode groups are to be employed.

It will also be noted that in the iinger tube just described the electron-emissive coating is employed as a cathode and that it is adapted to have potential from a circuit applied thereto.

I have found that the operation of the several linger tubes 28, 36, 32 and of the trunk tube 22 is appreciably enhanced by shielding said trunk and iinger tubes with an unsaturated but partially magnetized magnetic material.

The shield may take the form illustrated in Figs. 1 through 4, that is, it may comprise a main tubular portion H2 telescopically disposed around the trunk tube 22. Said tubular portion has a plurality of tubular projections H4, H6. H8 adapted to be telescopically received around the finger tubes 28, 39, 32 respectively. The shielding 'may .be constructed and assembled in any desired manner. For instance, the main tubular portion i l2 may comprise two adhesively joined segments to which the projecting tubular portions H4, H6 and H8 may be adhesively secured.

In accordance with my invention the substance from which the shielding is fabricated comprises a magnetic plastic. This includes a matrix of any plastic substance which is not deleteriously affected by the operating temperatures of they tube. By way of example, and without limiting myself to such materials, this substance may 7 compriseieither of the compositions known comlInerciallyV as Bakelite and Texolite Uniformly distributed throughout the plastic matrix are nely subdivided particles of a ferrous material such as soft iron, having a high magnetic permeability but incapable of retaining anything but aV slight residual magnetism. The plastic matrix also has uniformly distributed therethrough finely subdivided particles of a highly magnetically permeable material, Ysuch as steel, which is capable of retaining magnetism. This later substance before incorporation into the matrix is magnetized. Thus the magnetic plastic substance which shields the tube 20 at all times creates a magnetic field but is not satu,

rated. n

The presence of this field, I believe, caused by *ie tubular projections H, lili, H8 tends to force the electrons emitted from the electronemissive coatings of the nger tubes toward the center of such tubes so that they will be available in large quantities to conduct current betweenthe cathode and anode. In addition, during operation of the tube the electric fields induced by the operating current increases the magnetization of the shield by temporarily magnetizing lthe soit iron particles, thus enhancing the effect of the magnetic plastic shielding. I have also found that the magnetic plastic shield H2 around the trunk tube 422 reduces the power consumption thereof in'generation of the glow, thusincreasing the power eniciency of the tube 2o. This is probably due to the same cause as that explained with reference to the shields for the ringer tubes. The term power eiciency as used herein denotes the ratio between the quantity of electrons emitted by the electronemissive coatings and the amount of power required to emit such electrons.

It will be further appreciated that by energizing a plurality of iinger tubes from a single trunk tube the power eiciency of the tube 20, even when magnetic plastic shielding is not employed, is considerably greater than has heretofore been obtained.

Due to the exceedingly copious flow of electrons secured by the use of the coating previously described, it is even possible tooperate the nger tubes 28, (i0 and 32 in unevacuated envelopes. This adaptation of the finger tubes is rendered more efficient, of course, by the presence of the magnetic plastic shielding.

I found that the efhciency of the magnetic shielding is'increased by providing air gaps G each having a component running axially of the tubular portions of the shielding with which it is associated.

If desired, one or more of the finger tubes may be supplementally or even independently heated to the desired moderate emitting temperature by' a resistance lwinding |20 about such tube. This winding is illustrated in Fig. 1 in conjunction with the ringer tube 3s as a supplemental source of heat so that said tube can have a higher power output than the finger tube 32.

By supplying potential to the resistance winding |2i| from a portion of the circuit in which the'tube 30 is connected I may further periodicallyfstrengthen the magnetic eld forcing coated electronsto the center of the tube in phase with kthe periodic potential applied to the grid, thus increasing the sensitivity of the tube. For this purpose the resistance winding lill'i` is in thefiorm of a helix. wrapped around the tubular group |38. Said a,manchiz` magneti-c plastic shielding H0 to act as an inductance. Y f

Although I have illustrated the vseveral nger tubes supported on the trunk tube 22 as being-of `the same size and two of the nnger tubes as having different types of electrodes, it will beunderstood that these tubes may be of various sizes and all employ similar electrodes.

It will also be understood that, regardless off number, all or less than all of the finger tubes required in an electric circuit may be carried by the same trunk tube.

rIn Figs. '7 and 8, I have illustrated an electron tube |30 embodying another form of -my invention. In this form the glass Ytrunk tube |32, which functions in the same manner asgthe trunk tube 22, is enclosed for substantially its full length in a tubular glass envelope i3d. In the annular space provided between the envelope |34 and the external surface of the trunk tube, I dispose a plurality of electrode groups |30, |38, |40, each .of which is adapted to serve as an independent electronic tube.

The group |3 is adapted to act as a rectifier and includes a cathode m2 and anode Md. 'ihey cathode |42 is a foraminous tubular element of a conductive material which is telescopically disposed around and is coaxial with the tube |32. The anode is an imperforate tubular member of conductive material telescopically disposed around the cathode m2 and also arranged coaxially of the trunk tube |32. Both cathode and anode are connected by lead-wires Moto-prongs |48 projecting from the base |50 of the electrode base is secured in any suitable manner as by cementing to the outer envelope |34. The portion of the surface of the trunk tube |32 within the cathode layered electron-emissive coating |52, such as described with reference to Figs. 1 6. The axial dimensions 0f this coating |52, the cathode |42., and anode IM depend upon several factors, such, for example, as the power rating of the electrode group |35. If desired, the coating |52 may serve as the cathode, although it will be understood that the characteristics of the electrode group in such case, are not the same as that of the electrode rectifier group previously described.

In general, electrode groups |38 and l0@ may be constructed in the same manner as the electrode group |30. I have illustrated both of these groups as comprising the equivalents of conventional three-element vacuum tubes. One of said groups, for example, the group Hill, includes a cathode |54, a grid |50, and an anode |53. All of these electrodes are disposed concentricallyfof the trunk tube |32 and supported on lead-in wires |60 which are electrically connected to prongs |52 in the base |64 for said electrode group. Both the cathode and grid are foraminous. The anode, however, may be imperforate. The coating Itv associated with this electrode group |40 is ofthe same composition as that employed with the electrode group |36.

The cuter envelope der |68 of a magnetic plastic material such'as that described in the first embodiment of-my invention.

The annular space between and the envelope for the trunk tube is evacuated and free from oxygen. f

The prongs in the bases for the various electrode groups |36, |38, m0 can be connected to conventional tube sockets' by the detachable-` couplingssuch as the couplingsA 54-58 illustrated M2 vcarries a three-N lsi is shielded by a cyiinn the envelope |34' a conventional electronic tube socket. Said tube 4 includes an outer envelope |12 of magnetic plastic (Shown in dotted lines) such as that used to form the shields in the forms of my invention earlier described. The envelope |72 is of con-` ventional shape and includes a retroverted press |14, a conventional base |16, and projecting con- 'riecting prongs |18. A small glow discharge tube |80 is supported on the press |14 by lead-in wires |82, |84. The envelope of said glow tube |80 has on its external surface a coating such as described at length with respect to the ilrst embodiment of this invention. The cathode |85, grid |86, and anode |88 are all arranged concentrically of the discharge tube |80 and supported in this position by lead-in wires |90. Both the cathode and grids are foraminous and the anode imperforate.

It will be appreciated from the foregoing description that the electrode groups may be so designed as to accomplish any function of a present conventional electronic tube and they can thus be used as ampliers, detectors, oscillators, cathode ray tubes, etc.

It will thus be seen that there are provided devices which achieve the several objects of this invention and which are well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention and as various changes might be made in the embodiments set forth, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. An electronic tube comprising a member having a coating on said member adapted to emit a copious iiow of electrons at a mild temperature in the order of that generated by a positive column, electric discharge lamp, and means comprising a positive column, electric discharge lamp to heat said coating to such mild temperature, said coating comprising a base layer adjacent said member and consisting essentially of two finely sub-divided and intimately physically mixed and uniformly distributed substan-ces having diierent thermo-electric potentials, an electron-emissive layer on said base layer, said electron-emissive layer comprising an electron-emissive substance, and a layer of electrically conductive material intermediate said base layer and ,said member, the electrically conductive layer in- `cluding a metal from the group consisting of copper and silver, the base layer comprising copper .oxide and selenium, and the electron-emissive layer including an oxide selected from the group `consisting of barium oxide, strontium oxide, cesium oxide, virginium oxide and thorium oxide,

2. An electronic tube comprising a member "having a coating thereon which is energizable `upon heating to primarily emit a copious ilow of `electrons and which coating carries no electric charge during operation of the tube, heating means to energize said coating for primary electron-emission, a cathode electrically insulated from said coating, an anode also insulated from said coating, and means to provide a magnetic field around said cathode and anode for directing between said cathode and anode the electrons emitted from said coating.

3. An electronic tube comprising a member having ani electron-emissive coating thereon which carries no electric charge during operation of the tube, means to energize said coating to electron emission, a cathode electrically insulated from said coating, an anode, and means to provide amagnetic eld around said cathode and anode for directing the electrons emitted from said coating between said cathode and anode,

i said last named means comprising a shield surrounding said tube, said` shield being composed of a plastic matrix throughout which there is dispersed vnely sub-divided magnetic material.

4. An electronic tube comprising a member having an electron-emissive coating thereon which carries no electric charge during operation 'of the tube, means to energize said coating to from said coating,

electron-emission, a cathode electrically insulated an anode, and means to provide a magnetic eld around said cathode and anode for directing the electrons emitted from said coating between said cathode and anode, said last named means comprising a shield surrounding saidtube, said shield being composed of a .plastic matrixthroughout which there are dispersed finely sub-divided particles of temporarily highly m'agnetizable material and finely sub-divided permanently magnetized particles.

5. An electronic tube comprising a member having an electron-emissive coating thereon which carries no electric charge during operation of the tube, means to energize said coating to electron-emission, a cathode electrically insulated from said coating, an anode, and means to provide a magnetic iield around said cathode and anode for directing the electrons emitted from said coating between said cathode and anode, said last named means comprising a magnetic shield which has an air gap therein to prevent the formation of a complete magnetic circuit of low reluctance, said shield being composed of a plasti-c matrix throughout which there is -dispersed finely sub-divided magnetic material.

6. An electronic tube comprising a member having an electron-emissive -coating thereon which carries no electric charge during operation of the tube, means to energize said coating to electron-emission, la cathode electrically insulated from said coating, an anode, and means to provide a magnetic eld around said cathode and anode for directing the electrons emitted from said coating between said cathode and anode, said last named means comprising an inductive coil Wound around said tube.

7. An electronic tube comprising an elongated trunk tube, a plurality of nger tubes secured to said trunk tube and branching away therefrom, said branching tubes having electronemissive coatings therein which' are energizable upon being raised to a mild temperature in the order of that generated by a positive column electric dis-charge lamp to primarily emit a copious flow of electrons, each of said branching tubes having at least one group of electrodes therein into the space between which' electrons emitted by the coating are adapted to iiow, and means to cause a positive column electric .discharge in said trunk tube whereby to heat up said coatings for primary electron-emission. v

8. An electronic tube as set forth in claim 7 wherein a portion of a branching tube extends into said trunk tube.

9. An electronic tube as set forth in claim 7 y 11,0.An electronic tubeas set forth intclaim 7 wherein at least one. branching tube has a. portion projecting Within said trunk with ahigh heat conductivity ,means surrounding said portion.

11. An electronic tube Aas set forth in claim 7 wherein atv least one of said branching .tubes i communicates with the interiorof said-'trunk tube.

12. An electronic tube asset forth inclaim 7 wherein at least one of said branching tubes communicates with-thel interorof rsaid. trunk tube and has'a screening electrode disposed in the pas- Sageway connecting said` trunk tube andsaid branching'tube.

13. vAn electronic tubeucomprsing anelongated trunk tube, meansy to causea glcw'dscharge in Said trunk` tube, and a plurality of tubes secured Y to; said trunk tube. and branching away therefrom, `said-branching tubes having electron-emissive coatings ltherein which are energized `to electron-emission by the heatgenerated by said discharge, each of saidI branching/tubes havingV at least one vgroup of' electrodes therein, at least one ofV thel electrode groups comprisingan anode and a grid telescopically around the, same, fthe coating beingV disposed, on the; interior surface'. of

tube and is provided-` 12 an envelope of: .the `,branching tubeA for. said {e1-ectrodegroup.. f' .1x Y ORLOVE.

REFERENGESCITED The following refe'relrlcesare of*frecordiinv the le ofv'this patent: 1

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